So I bought my car and it already had an alpine head unit and 5 channel alpine amp. However I was blessed with the stock Nokia sub system. Since I'm not limited to the stock dsp amp and OEM setup what do you guys have as far as ad ice for increasing the audio's low end? I really like the M Audio's ability to maintain trunk space. I am therefore curious what alternatives the rest of you have come up with. Unlike my E46 M3, I assume that since BMW fitted subs to the chassis that low excursion smallish subs wouldn't be an vibration issue. However I would love to hear your experiences.